The use of cationic materials to treat hair in a post-shampoo rinse is a well-know cosmetic practice. Likewise, the use of softeners to treat fabrics after a washing operation is a well-known laundering practice. Fabric softeners are, in the main, water-insoluble cationic materials that are incompatible with anionic detersive surfactants used in most fabric washing compositions. For that reason, the softening operation is generally carried out in the laundry rinse bath after the surfactant has been removed from the washing machine. This entails additional work for the user.
Formulators of fabric laundering compositions have long sought means whereby the fabric washing and softening could be done concurrently. The same is true for shampoo formulators, since the problems are rather similar. Laundering methods employing clay softeners, mixtures of clays and various amine materials and the like, are described in the following patents: German Nos. 29/64114.3, 28/57163.3, 24/39541.3, 23/34899.4 and EPO Nos. 80200570.2, 80200877.1 and 80201015.7. The use of mixtures of amines and soaps (salts of fatty acids) as through-the-wash softeners is disclosed in U.K. Pat. No. 1 514 276.
The prior art also describes the use of various cationic materials in sheet form. See U.S. Pat. No. 4, 220, 562.
The present invention employs alkyl amide derivatives of copolymers in laundry or shampoo compositions to provide cleaning and softening concurrently. The amidesubstituted copolymers herein provide improved softening and anti-static benefits, especially when used with clay softeners and/or when the compositions herein are used at moderate laundering temperatures (up to 60.degree. C.). In contrast with monomeric amides taught for use in detergents by the prior art, the amide/copolymers herein are heat-stable, and can be used in aqueous crutcher mixes to provide spray-dried detergents.